Anti-government protesters wearing costumes march during Halloween in Lan Kwai Fong, Central district, Hong Kong, Oct. 31, 2019.
Anti-government protesters wearing costumes march during Halloween in Lan Kwai Fong, Central district, Hong Kong, Oct. 31, 2019.

Hong Kong Police fired tear gas Thursday on masked pro-democracy protesters and Halloween revelers in the territory's nightlife district.

Riot police began firing tear gas shells after the demonstrators urged others to celebrate Halloween wearing masks, including those depicting Carrie Lam, the city's embattled chief executive, Chinese President Xi Jinping or other government officials.

Protest organizers appealed to supporters to wear face coverings to test the city's recent emergency law banning masks at public gatherings.

Police slowly pushed back people from the Lan Kwai Fong district but it was not immediately clear if clashes had occurred or if there were arrests.

Police also fired tear gas to disperse hundreds of protesters, many wearing masks, on one of the major thoroughfares in Kowloon, an area in northern Hong Kong on the other side of Victoria Harbor.

Hong Kong police say they would deploy extra officers to the Lan Kwai Fong district and would demand anyone suspected of being a protester to remove their masks or facepaint.  But Halloween masks are not covered under the ban, which will make it difficult for police to tell the difference between a protester and an ordinary reveler.

Thousands of masked demonstrators have marched through Hong Kong's streets since June, sparked by anger over a controversial extradition bill that evolved into demands for full democracy for the Chinese-controlled city. The protesters have hidden their identities out of fear of retribution from local authorities, or concerns they could be shared with mainland China.

Hong Kong earlier this month banned people from wearing masks at public protests by invoking a British colonial-era emergency powers act that was last used to quell riots in in 1967.  The current ban was invoked in response to increasingly violent clashes between police and protesters.  

The turmoil, coupled with the ongoing U.S.-China trade war, has taken a toll on the financial hub, with the government announcing Thursday that the city is in a technical recession for the first time in a decade.